What factor is primarily responsible for the movement of electrons in a circuit?

The primary factor responsible for the movement of electrons in a circuit is voltage. Voltage, or electric potential difference, is what drives electrons to move through a conductor. It provides the necessary energy to overcome resistance within the circuit, enabling current flow. When voltage is applied across a circuit, it creates an electric field that pushes the electrons, resulting in an electric current.

Resistance plays a role in the flow of electrons by opposing that flow, but it does not cause movement itself. Energy is a more general concept and describes various forms of power transfer, rather than being a specific driver of electron movement in this context. Frequency relates to the changes in the signal or flow, not the initial cause of electron movement. Thus, voltage is the essential factor that instigates and sustains the flow of current in an electrical circuit.